Sooo I'm missing the point of this thread then. Get the ROMs (important: make sure you get the extra patches from romhacking that fix the commonly-available translation's errors and bugs!), and see if they run well enough for you. 1,4 mb worth of downloads is not a lot, especially compared to keeping RXTools up to date.
Retroarch does not give higher FPS for SNES emulation on a 3DS as far as I know?
And yes, aside from 1.3c there was a thread here on GBAtemp where some folks modified the visual code to use 3D mode to effectively double the vertical resolution of the top screen. It's a nice difference. I'd need some time to dig out the link though, as i'm on mobile right now.